Jiming Yang, The Error Analysis of An Upwind Difference Approximation for a Singularly Perturbed Problem. journal = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology. April 2011, vol. 52(4). 621 - 623 [viewed 20 September 2024]. Available from: https://publications.waset.org/pdf/9939.